WASHINGTON — An appeals court has ruled, for the time being, against groups that finance electioneering ads and want to keep the identity of their donors secret.

In a 2-1 decision late Monday, the U.S. Court of Appeals for the District of Columbia Circuit said the groups provided no evidence their contributors would face threats if their names were disclosed. The merits of the case will be argued before the appeals court in September.

The disclosure issue involves broadcast ads that don’t expressly advocate for or against a candidate running for office.

A federal judge ruled in March that the Federal Election Commission overstepped its bounds in allowing groups that fund the ads to keep their financiers anonymous. The funding groups had sought to have that ruling put on hold.

Rep. Chris Van Hollen, D-Md., filed the original lawsuit to overturn the FEC regulation. One of his attorneys, Democracy 21 President Fred Wertheimer, said the case is part of a concerted effort to end secrecy in the campaign finance arena.

Other efforts include legislation sponsored by Sen. Sheldon Whitehouse, D-R.I., and Van Hollen to require more detailed disclosure requirements for campaign finance.

In addition, Democracy 21 and another organization, the Campaign Legal Center, are challenging the tax-exempt status of several funding groups classified as social welfare organizations, a designation which allows the groups to keep their donors’ contributions secret. One of the social welfare organizations, American Crossroads GPS, is an arm of American Crossroads, a super PAC with ties to President George W. Bush’s longtime political director, Karl Rove.

Another social welfare organization, Priorities USA, is backing President Barack Obama.